Printing block and method of making same



jan. 9, 1934. i Bl C.. CHAMBERS Iz PRINTING BLOCK AND'METHOD OF MAKINGSAME Filed April 21. 1930 INVENTOR Patented Jan. 9, 1934 UNirED STATESrA'rsNr -oi-Flcg PRINTING BLOCK AND METHOD @F MARIN G SAME ApplicationApril 2l, 1930. Serial No. 445,853

3 Claims.

My invention relates to printing blocks and methods of making printingblocks.

The object of the invention is to improve the construction of printingblocks useable for example in certain multi-color printing -processesand to facilitate and otherwise improve the method of making printingblocks useable insuch processes.

Other objects will be in part apparent to those skilled in the art or inpart pointed out hereafter.

The invention consists in the features of construction, combination ofelements, arrangement of parts, and in the method and combination ofsteps, as will be exemplified in the structure and method hereinafterdescribed, and the scope of the application of which will be indicatedin the following claims:

In order that the invention may be readily understood and its advantagesfrom a practical standpoint appreciated, reference may be had to theaccompanying drawing showing one of the preferred forms of embodiment`which the printing block of the present invention is adapted to take.

In the drawing, Fig 1 is a plan view of a printing block made inaccordance with my invention before incising and stripping; Fig. 2 is acrosssectional view through said block on the line to 2-.2 in Fig. 1;Fig. 3 is the block of Fig. 1 after it has been incised and stripped toprint the design shown; and Fig. 4 is a cross-sectional view partly inelevation on the line 4 4 in Fig. 3 looking in the direction of thearrows. The same numerals refer to similar parts throughout.

Referring to the drawing, the printing block there illustrated isgenerally designated by the letter A and comprises a lead plate l, alayer of fabric 2 cemented on said lead plate, and a thin rubber layer 3cemented on said fabric so as to be strippable therefrom. The lead platel and the fabric layer 2 together constitute a supporting base for thelayer of rubber 3.

'I'he design to be printed is laid out on the surface of the rubberlayer and its outlines are then cut through the rubber layer down to thefabric layer. which are not to be inked or printed from are stripped andremoved from the fabric layer ,whereby the design, or other subjectmatter to beprinted, -standsup in relief from the fabric designvraised'ir'i'V relief on the fabric layer 2, the

Then those portions of the rubber layer,l

(Cl. Mil-395) surface of which is inked or receives the color when usedfor printing copies in a printing' press. Adjacent to said raisedportions' 3a in the drawing are the spaces from which .the rubber layerhas been stripped down to the fabric layer and which is at a levelsuitably below the printing surface of the parts 38 representing thedesign. v

The part 1 of the printing block maybe made of any suitablenon-resilient supporting'I material suchA as wood, lead, etc. Springymaterial such as sheet steel or copper is preferably avoided. The rubberlayer 3 may be applied directly to the, block or plate 1 but I prefer touse an intermediate layer 2 of a substantial but non-rigid or nonhardnature such as two or three-ply canvas with its layers united byrubber-cement or similar material. One advantage of interposing such anintermediate layer between the rubber layer 3 and the metal plate 1 isthat the point of the cutting tool is not dulled or turned by theintermediate layer which it would be by the plate when cutting throughthe rubber layer preparatory to stripping. Another advantage is that theintermediate layer or layers can be cut through as to portions thereof;and stripped from the plate 1 where it is desirable or necessary to givegreater depth to the spaces adjacent the printing portions Bi as will beexplained later. Moreover, the described portions 2 and 3 may consist ofa composite of separable rubber layers on a plate 1, said layers beingindependently or separately strippable from each other as well aspreferably from said plate.

The invention provides a printing block in which the design (meaningdesign proper, lettering or any other subject matter) can be formed inrelief quickly and accurately. The design having been laid out on thesurface ofthe rubber layer 3, the rubber layer is cut through with asharp knife peripherally about the non-printing portions of the rubberlayer viz those portions which are not to be inked or printed from. Thishaving been done, 'said non-printing portions are stripped from theintermediate layer thereby leaving in relief the printing portions 3e ofthe rubber layer.

In case in any given printing block, prepared as above, there is anextra large space or area of exposed intermediate layer between printing'portions 38L which the sheets being printed might belly into and becomesmudged by contact with the intermediate layer, this is easily remediedwith printing blocks or platesmade up accorde ing to my invention byperipherally cutting through said interfering portion of the intermesaiddiiliculty is quickly remedied With'my print-- ing block whereby theprinting portions 3 may be caused to stand up with any desired extent ofre- Alief by providing multiple strippable layers on the support whichcan be: cut through and stripped off one after the other according tothe extent of relief desired for the printing surfaces of the block.

The'invention is a decided improvement over the existing methods ofmaking up color printing blocks and the like which had a relativelythick rubber layer on a wooden or metal backing and which vrequired thedesign to be gouged or routed out of the surface portion of the rubber.VThis is a considerably longer and more difficult process and not soaccurate as the simple procedure permitted by this invention of merelycutting the design through the thin rubber layer to the intermediate orthe next layer, if there be more than one intermediate layer, and thenstripping away those parts of the rubber and other layers which are notwanted for printing surfaces inthe finished block or which wouldotherwise interfere with the proper use of the block.

Rubber is the preferred material for the printing layer 3, but it ispossible to substitute for it an equivalent material which will properlyreceive and print colors and vwhich can be readily out through andstripped.

It will be understood that this invention is not limited to thepreferential embodiment but that modifications may be made in saidembodiment and in the described method without departing from the scopeand spirit -of the invention.

What I claim isz- 1. The method of preparing a printing block or platethat has a rubber layer strippably secured to an intermediate layer,which is in turn strippably secured on a substantially rigid base, whichmethod comprises cutting through the rubber layer down to theintermediate layer periphorally about the non-printing portions of therubber layer; stripping off said portions from the intermediate layer soas to leave in relief thereon the printing portions of lthe rubberlayer; and

vcutting through the exposed intermediate layer peripherally about thoseportions thereof which it is desirable'to remove and stripping of'same'.

2. The method of preparing a printing block or plate having a designdelineated thereon in relief between relatively large and relativelysmall nonprinting areas, and having a rubber layer strippably secured toan intermediate layer, which in turn is secured to a substantiallynon-resilient base,: which method comprises'cutting through the rubberlayer down to the intermediate layer peripherally about the non-printingareas, and

'cutting also through the intermediate layer peripherally about therelatively large non-printing areas, and stripping and removing saidportions from the respective-layers so as to leave in relief thereonthev printing portions of the rubber layer.

3. The method of preparing a printing block or plate having a designdelineated thereon in reliefv between relatively large and relativelyvs'mall non-printing areas, and having a plurality of resilient layersstrippably secured to each other and to a substantially non-resilientsupport, which method comprises' cutting through the outer layerperipherally about the design and stripping all the non-printing areasthereof from the adjacent layer, and then cutting through the saidadjacent layer about the relatively large nonprinting areas only andstripping the said adjacent layer from its support at those areas.

BERT C. CHAMBERS'.

